Re: Web server access

["Mark Harrison (Groups)" <mph@xxxxxxxxxxxxxxx>]

On Sat, 2005-08-13 at 21:02 +0100, Alex Clark wrote:

A lot hinges on how sophisticated your router is. Start with Option 1
and work down till you find something that works on your hardware :-)


Option 1: Real PAT

In an ideal world, what sir wants is something called "Port address
translation" (PAT).

Suppose you have three internal boxes:

webserver 	192.168.0.1
cameraserver	192.168.0.2
fileserver	192.168.0.3

each running a webserver on port 80.

With some routers / firewalls, you can set things up so that (if you
have external IP 1.2.3.4 then:

- 1.2.3.4:80 -> 192.168.0.1:80
- 1.2.3.4:81 -> 192.168.0.2:80
- 1.2.3.4:82 -> 192.168.0.3:80

The problem is that some domestic routers don't allow you to do this.
They only allow you to do NAT (Network address translation.) So you go
to:


Option 2: Port-specific NAT

Some routers allow you to do DIFFERENT network address translation based
on ports.

You first reconfigure cameraserver so that it runs on port 81 rather
than 80, then fileserver so it runs on port 82 rather than 80.

Then you set up NAT so that:

- 1.2.3.4:80 -> 192.168.0.1:80
- 1.2.3.4:81 -> 192.168.0.2:81
- 1.2.3.4:82 -> 192.168.0.3:82

However, it may be that your router doesn't even allow this, so you turn
to the dark world of:


Option 3: Reverse proxy server

You can set up some webserver so that THEY manage the stuff for you. In
this case, you could configure a new box (or add config to one of the
existings) so you have:

reverseproxy 	192.168.0.4

You then set up your router so that all traffic on port 80 goes to that
box.

You then configure reverseproxy so that:

http://reverseproxy/webserver
-> 192.168.0.1
http://reverseproxy/cameraserver
-> 192.168.0.2
http://reverseproxy/fileserver
-> 192.168.0.3

'tis, alas a bit of a black art. If you're going to use Apache server to
do it, then I can send bits of config. If you're going to use IIS, then
there are others here who can help.


HTH

M.